December 22, 1892] 



NA TURE 



189 



but Dulong and Petit's values are too high, and Rosetti's too 

 low. — Notes on silver, by M. Carey Lea. — Notes on silver 

 chlorides, by the same. Fused silver chloride poured into 

 petroleum and placed in the sunlight without removing it from 

 the liquid, is instantly darkened. From this it appears that the 

 presence of oxygen or moisture is not essential to the darkening 

 of silver chloride in light. The chlorine may be taken up by 

 ^ome other substance. — A remarkable fauna at the base of the 

 Hurlington Limestone in north-eastern Missouri, by Charles 

 Ro'lin Keyes. — Glacial pot-holes in California, by H.W.Turner. 

 — The lavas of Mount Ingalls, California, by H. W. Turner. 

 — A method for the quantitative separation of barium from stron- 

 tium by the action of amyl alcohol on the bromides, by Philip 

 E. Browning. The solubility of barium bromide is about o '0013 

 t;rm. on the oxide in 10 cc. of amyl alcohol, while that of stron- 

 tium bromide is 0*2 grm. To obtain the bromides, the pre- 

 cipitated and thoroughly washed carbonates of Ba and Sr are 

 treated with hydrobromic acid obtained by the action of dilute 

 sulphuric acid on potassium bromide. — Note on the method for 

 the quantitative separation of strontium from calcium by the 

 action of amyl alcohol on the nitrates, by P. E. Browning. 

 Recent work on this method has shown that the total correction 

 amounts to o-ooo6 grm. on the strontium oxide, and oooio on 

 the calcium as sulphate. — Study of the formation of the alloys 

 of tin and iron, with descriptions of some new alloys, by W. P. 

 Ileadden. — Notes on the Cambrian rocks of Pennsylvania and 

 Maryland from the Susquehanna to the I'otomac, by C. D. 

 Walcott. — Volcanic rocks of South Mountain in Pennsylvania 

 and Maryland, by G. H. Williams. 



Wiedemann s Annalen der Physik und Chemie, No. II. — On 

 the behaviour of allotropic silver towards the electric current, 

 by A. Oberbeck. — On the indices of refraction of dilute 

 solutions, by W. Hallwachs. — On capillary constants, by M. 

 Cantor. — On the chemistry of the accumulator, by M. Cantor. 

 — On the fall of potential during discharges, by O. Lehmann. 

 A series of important investigations on discharges between 

 electrodes and in tubes without electrodes. — Expansion of water 

 with the temperature, by K. Scheel. — A method for determining 

 the density of saturated vapours and the expansion of liquids at 

 higher temperatures, by B. Galitzine. This method has the 

 advantage of extreme simplicity combined with accuracy. A 

 small glass tube, about 5 cm. long and a few mm. thick, is 

 closed at one end and drawn out into a capillary at the other. 

 After determining the weight and internal volume of the tube, 

 a small quantity of the substance to be investigated is introduced 

 into it in the liquid state. This is made to boil, and then the 

 tube is sealed by fusing. On raising the temperature, the sur- 

 face of separation between the liquid and its vapour is 

 displaced, until at a certain temperature all the liquid is 

 converted into saturated vapour. The tube is then cooled until 

 the vapour reappears, when the temperature is again taken. 

 This can be repeated several times, thus giving an accurate value 

 for the density of saturated vapour at a certain temperature. 

 The same process can be used to determine the expansion of the 

 liquid. As the temperature rises, the volume of the liquid will 

 in general increase up to a certain point, when the vaporization 

 becomes more pronounced. This maximum, which can be ob- 

 served more accurately by drawing out the tube near that point, 

 gives a value for the expansion. For the density at that point 

 I is a function of the density at 0° C. and the temperature, 

 I and the pressure is that of the saturated vapour at the same 

 ■ temperature. Thus it is only necessary to find the volumes of 

 i the liquid and the vapour, and the density of the latter from the 

 previous experiment. — On radiant energy, by B. Galitzine.-^ 

 Note on the electricity of waterfalls, by J. Elster and H. Geitel. 

 — Apparatus for demonstrating the Wheatstone bridge arrange- 

 ment, by A. Oberbeck. — Determination of the coefficient of 

 self-induction by means of the electro-dynamometer, by O. 

 Troje. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, December 15.— On some new reptiles from 

 the Elgin Sandstone, by E. T. Newton, communicated by Sir 

 Archibald Geikie, F.R.S. 



During the last few years a number of reptilian remains have 

 been obtained from the Elgin Sandstone at Cuttie's Hillock, 



NO. 1208, VOL. 47] 



near Elgin, which are now in the possession of the Elgin 

 Museum and of the Geological Survey. These specimens repre- 

 sent at least eight distinct skeletons, seven of which undoubtedly 

 belong to the Dicynodontia, and one is a singular horned reptile, 

 new to science. All the remains yet found in this quarry are in 

 the condition of hollow moulds, the bones themselves having 

 entirely disappeared. In order, therefore, to render the speci- 

 mens available for study, it was necessary, in the first place, so 

 to display and preserve these cavities that casts might be taken 

 which would reproduce the form of the original bones. Gutta- 

 percha was found to be the most suitable material for taking 

 these impressions ; and in some instances, especially in the case 

 of the skulls, the casts had to be made in several parts and after- 

 wards joined together. 



The first specimen described is named Gordonia Traquairi ; 

 it is the one noticed by Dr. Traquair in 1885, and referred to the 

 Dicynodontia ; besides the .skull, it includes fragmentary portions 

 of other parts of the skeleton, and is contained in a block of sand- 

 stone which has been split open so as to divide the skull almost 

 vertically and longitudinally. The two halves have been so 

 developed that casts made from them exhibit the left side and 

 upper surface, as well as the main pans of the palate and lower 

 jaw. In general appearance this skull resembles those of Dicy- 

 nodon and Oudenodon. The nasal openings are double and 

 directed laterally ; the orbits are large and look somewhat for- 

 wards and upwards. The supra-temporal fossa is large, and 

 bounded above by the prominent parieio squamo^^al crest, and 

 below by the wide supra-temporal bar, which extends downwards 

 posteriorly to form the long pedicle for the articulation of the 

 lower jaw. There is no lower temporal bar. The maxilla is 

 directed downwards and forwards to end in a small tusk. Seen 

 from above, the skull is narrow in the inter-orbital and nasal 

 regions, but wide posteriorly across the temporal bars, although 

 the brain-case itself is very narrow. There is a large pineal 

 fossa in the middle of a spindle-shaped area, which area is formed 

 by a pair of parietals posteriorly and a single intercalary bone 

 anteriorly. 



The palate is continuous with the base of the skull ; the 

 pterygoids on each side send off a distinct process to the quadrate 

 region. Towards the front the mediam part of the united 

 pterygoids arches upwards, and the outer sides descend, forming 

 a deep groove ; from the evidence of other specimens it is clear 

 that the palatines, extending inwards, converted this groove into 

 a tube, and thus formed the posterior nares. The ramus of the 

 lower jar is deep, with a large lateral vacuity, and the two rami 

 are completely united at the symphysis. The back of this skull 

 is not seen, but two other specimens, referable to this same 

 genus, show that the occiput had two post-temporal fossje on 

 each side. 



This specimen is distinguished from Dicynodon by the pres- 

 ence of two post- temporal fossae on each side of the occiput, by 

 the small size of the maxillary tusk ; and probably by the 

 elongated spindle-shaped area enclosing the pineal fossa, and 

 also by the slight ossification of the vertebral centra. 



A second and much smaller specimen, provisionally referred 

 to G. Traquairi, has, besides the skull, a fore-limb well pre- 

 served. Ihe humerus of this shows the usual Anomodont 

 expansion of its extremities ; its large deltoid crest is angular, 

 and set obliquely to the distal end. 



Three other species are referred to the same genus, namely : — 



Gordonia Huxleyana, which is distinguished from G. Traquairi 

 by its proportionately wider and more depressed skull, and by 

 the absence of the concavity between the orbits which is present 

 in the latter species. The humerus has the distal extremity 

 oblique to the deltoid crest, which was probably rounded and 

 not angular. 



G. Duffiana has the skull even wider than in G. Huxleyana, 

 and the portion of a humerus found with this skeleton has the 

 two extremities set nearly at right angles to each other. 



G. Juddiana has an elongated skull resembling that of G. 

 Traquairi, but the parietal crests are less developed, the bones 

 of the nasal region are much thickened and overlap the nasal 

 apertures, the small tusk is placed a little further back and 

 points more directly downwards, and the pineal fossa is 

 smaller than in either of the other species. 



A second generic form is named Geikia Elginesis. This is a 

 skull nearly allied to Piychognathus, Owen, but is distinguished 

 by its shorter muzzle and the entire absence of teeth ; the upper 

 part of the skull, between the orbits, is also peculiar, forming a 

 deep valley open anteriorly, with a ridge on each side, the anterio 



